package com.example.test.netty.utils;

import org.springframework.web.multipart.MultipartFile;
import sun.misc.BASE64Decoder;

import java.io.*;

/**
 * @program: test
 * @description: Base64图片转MultipartFile
 * @author: qiu bo yang
 * @create: 2020-10-14 16:58
 **/
public class Base64DecodedMultipartFileUtils implements MultipartFile {
    private byte[] imgContent;
    private String header;

    public Base64DecodedMultipartFileUtils() {
    }

    public Base64DecodedMultipartFileUtils(byte[] imgContent, String header) {
        this.imgContent = imgContent;
        this.header = header.split(";")[0];
        ;
    }

    @Override
    public String getName() {
        return System.currentTimeMillis() + Math.random() + "." + header.split("/")[1];
    }

    @Override
    public String getOriginalFilename() {
        return System.currentTimeMillis() + (int) Math.random() * 10000 + "." + header.split("/")[1];
    }

    @Override
    public String getContentType() {
        return header.split(":")[1];
    }

    @Override
    public boolean isEmpty() {
        return imgContent == null || imgContent.length == 0;
    }

    @Override
    public long getSize() {
        return imgContent.length;
    }

    @Override
    public byte[] getBytes() throws IOException {
        return imgContent;
    }

    @Override
    public InputStream getInputStream() throws IOException {
        return new ByteArrayInputStream(imgContent);
    }

    @Override
    public void transferTo(File dest) throws IOException, IllegalStateException {
        new FileOutputStream(dest).write(imgContent);
    }

    /**
     * 将base64图片转MultipartFile
     *
     * @param base64Str base64字符串
     * @return
     */
    public static MultipartFile base64ToMultiFile(String base64Str) {
        try {
            String[] baseStr = base64Str.split(",");
            BASE64Decoder decoder = new BASE64Decoder();
            byte[] b = decoder.decodeBuffer(baseStr[1]);
            for (int i = 0; i < b.length; ++i) {
                if (b[i] < 0) {
                    b[i] += 256;
                }
            }
            return new Base64DecodedMultipartFileUtils(b, baseStr[0]);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

}
